How do I display a property in the viewport without using a modal operator?
Extending the code from Draw and update text in viewport without modal operator in blender

I suggest using a class to handle the handles, and pass context to the callback method.

import bpy
import blf

class DrawingClass:
    def __init__(self, context, prop):
        self.prop = prop
        self.handle = bpy.types.SpaceView3D.draw_handler_add(
                   self.draw_text_callback,(context,),
                   'WINDOW', 'POST_PIXEL')

    def draw_text_callback(self, context):
        font_id = 0  # XXX, need to find out how best to get this.

        # draw some text
        blf.position(font_id, 15, 50, 0)
        blf.size(font_id, 20, 72)
        blf.draw(font_id, "%s %s" % (context.scene.name, self.prop))



    def remove_handle(self):
         bpy.types.SpaceView3D.draw_handler_remove(self.handle, 'WINDOW')

context = bpy.context             
dc = DrawingClass(context, "Draw This On Screen")

#dc.remove_handle()  # will remove the handle and stop drawing